JP3982123B2 - Roller manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for manufacturing an elastic roller such as a developing roller, a charging roller and a transfer roller incorporated in an electrophotographic apparatus employing an electrophotographic process in an image forming apparatus such as a copying machine, a laser printer or a facsimile receiver. It is.
[0002]
[Prior art]
As a roller incorporated in the electrophotographic apparatus, a charging roller for charging the surface of an electrostatic latent image carrier such as a photosensitive drum, and toner is supplied to the electrostatic latent image carrier to develop the latent electrostatic image. There are elastic rollers such as a developing roller, a transfer roller that transfers the exposed toner image to a sheet, and a cleaning roller that removes residual toner on the electrostatic latent image carrier after transfer.
As a method for manufacturing this type of elastic roller, an injection molding method is widely known. In recent years, with the increase in demand for this type of elastic roller, competition for price reduction has intensified, and there is an urgent need for a roller manufacturing apparatus that can be manufactured at the lowest possible cost.
[0003]
FIG. 2 is a schematic cross-sectional view showing a typical example of a conventional injection mold. In the figure, reference numeral 41 is a cylindrical mold, 42 is a core metal inserted into the cylindrical mold 41, 43 and 44 are core metal holding members, and 45 and 46 are cover members provided with screwing grooves on the inner surface. , 47 indicate pins. The procedure for molding an elastic roller using such an injection mold is as follows. First, the core metal 42 is inserted into the cylindrical mold 41, and both end portions 42a and 42b thereof are fitted into the core metal holding holes 43a and 44a provided in the core metal holding members 43 and 44, respectively. , 44 are fitted into the cylindrical mold 41, and then the cover members 45, 46 are screwed into the cylindrical mold 41 so as to cover them, thereby forming a roller molding space 60 and closing the injection mold. To.
[0004]
Next, a resin injection nozzle (not shown) is applied to the nozzle mounting hole 49 provided in the cover member 46, and the resin material is injected into the roller molding space 60 through the resin injection hole 44 b formed through the core metal holding member 44. After filling, the gas vent hole 50 penetratingly formed in the cover member 45 is closed with a pin 47 and then closed, and then the cylindrical mold 41 is heated to heat and cure the resin material. As a heating means, there are those in which a heating mechanism (not shown) is brought into contact with the outer surface of the cylindrical mold 41, and those in which the injection mold is transferred into a hot stove (not shown) and heated. is there. After the heat curing, the cylindrical mold 41 is cooled, the mold is opened in the reverse procedure to the above, the molded product is released, and then the above procedure is repeated again to produce a new molded product.
[0005]
[Problems to be solved by the invention]
However, the conventional roller manufacturing apparatus as described above has the following problems. In the process of manufacturing a roller, when releasing a molded product from a cylindrical mold, there is a considerable resistance to releasing the mold. Treatment and fluorine coating treatment are applied. However, by repeating the molding in accordance with the above procedure, only the inner surface of the cylindrical mold is inevitably deteriorated such as wear and scratches, and the effective life is about 1000 times. The deteriorated cylindrical mold is subjected to maintenance such as re-plating and then used again. However, once maintenance is performed, the inner diameter of the cylindrical mold slightly changes and the roller is changed. From the viewpoint of obtaining a stable quality, it is preferable to update the cylindrical mold. Even if maintenance such as re-plating treatment is performed on the cylindrical mold, or the cylindrical mold is newly replaced, in both cases, it is necessary to remove and install the cylindrical mold. However, in the conventional injection mold, this operation is complicated and not suitable for automation, and there is a limit to the positioning accuracy when mounting the cylindrical mold, which reduces the cost of the roller and improves the roller quality. It was the cause that obstructed.
For example, in the conventional injection mold, the process of mounting the cylindrical mold includes a step of fitting the core metal holding members 43 and 44 into the cylindrical mold 41 and screwing the cover members 45 and 46 together. However, if the tightening load at the time of screwing is too large in this operation, the core metal 42 is likely to buckle due to an excessive load, and if the tightening load is too small, the pressure of the filling resin The material leaks out and burrs are generated in the molded product, which lowers the moldability of the roller. It is difficult to automate such delicate adjustments at a low cost, and it is still a fact that there is no choice but to rely on human hands. In addition, in order to smoothly attach and detach the core metal holding member to the cylindrical mold, a certain clearance is required between them, and this improves the positioning accuracy of the cylindrical mold and the core metal holding member. As a result, there were defects such as large roller runout.
In view of the above problems, the present invention intends to solve the problem that the structure of the cylindrical mold is simple and the cost burden due to the replacement of the cylindrical mold can be reduced. The present invention is to provide a roller manufacturing apparatus that is suitable for automating the installation work in the interior and that can be easily centered with a small amount of roller deflection.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventor has conceived to reduce the cost of the roller manufacturing apparatus by simplifying a cylindrical mold having a relatively short life without adding an extra function, and this cylinder. The present invention has been completed as a result of studies on an apparatus structure suitable for automating the work of removing and mounting the mold and the installation in the cylindrical mold.
[0007]
The present invention that has solved the above problems is an apparatus for manufacturing a roller in which a synthetic resin layer is coated on the outer periphery of a metal core over the longitudinal direction,
A space having a cylindrical shape in which a mandrel is provided with a synthetic resin-filled space around it, with a predetermined range from the opening end as an inclined inner peripheral surface, and an inner diameter expanding toward the opening end at both ends in a predetermined range A cylindrical mold formed with,
A member that is disposed at both ends of the cylindrical mold and that closes the open end of the cylindrical mold while holding the end of the core metal, has an inclined outer peripheral surface, and receives and holds the shaft end of the core metal. A cored bar holding member provided with a chevron fitting body that complementarily fits in the diameter-enlarged space of the cylindrical mold having a shaft end holding hole in the radial center;
A base mold having a through hole with an inner diameter slightly larger than the outer diameter of the cylindrical mold for mounting the cylindrical mold; and a member that covers the outer peripheral surface of the cylindrical mold.
And a means for fastening the cored bar holding member to both ends of the base mold.
[0008]
The clearance between the outer diameter of the tube mold and the inner diameter of the base mold is preferably 0.01 to 0.1 mm.
[0009]
When the flanges of the base mold and the core metal holding member are provided to face each other, and when the collar part of the base mold and the collar part of the core metal holding member face each other, inclined outer peripheral surface and the inclined inner peripheral surface of the cylindrical mold is set at a position abutting relationship over the entire surface, such that the chevron fitting member is complementarily tightly fitted in enlarged space of the tubular mold It is desirable to set the formation position of the buttock.
[0010]
Moreover, it is preferable that the back side of the face to be joined of the flanges facing each other is an inclined surface, and the outer surface of the buttocks in contact is fastened with a ferrule clamp.
A curable liquid resin can be used as the synthetic resin layer covering the outer periphery of the cored bar.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the roller manufacturing apparatus of the present invention will be described based on the illustrated embodiments.
FIG. 1 shows a typical embodiment of a roller manufacturing apparatus according to the present invention. This apparatus is an apparatus for manufacturing a roller in which a synthetic resin layer is coated on the outer periphery of the core bar in the longitudinal direction except for both ends. The specific shape of the roller is not limited. The shape may be straight without a step or may have a step. The material of the metal core is not particularly limited as long as it is a metal material, but the use of a material having a significantly different thermal expansion coefficient from the material of the apparatus should be avoided.
[0012]
As a material for the resin layer of the roller, various synthetic resin materials such as silicone, urethane, NBR, and EPDM are selected. In this embodiment, for example, a curable liquid resin such as silicone is used. A curable liquid resin is suitable because it has a low viscosity and can be injected at a low injection pressure.
As shown in FIG. 1, the manufacturing apparatus includes a cylindrical mold 1, core metal holding members 3 and 4 positioned at both ends of the cylindrical mold 1, and a base mold 10 that covers the outer periphery of the cylindrical mold 1. And ferrule clamps 21 and 22 for fastening the core metal holding members 3 and 4 to the base mold 10. The upper and lower core metal holding members 3 and 4 have functions of holding the upper and lower shaft end portions 2a and 2b of the core metal 2 housed in the cylindrical mold 1 and closing the open end of the cylindrical mold 1. is doing. The figure shows a cross section in a state where the roller manufacturing apparatus is assembled before the resin is injected.
[0013]
The cylindrical mold 1 has a roller molding space 30 that is a space for receiving a core metal 2 and molding a resin molding around the core metal 2, and a predetermined range d from the opening end to the inclined inner peripheral surfaces 1 a and 1 b. Thus, a space in which the inner diameter increases toward the opening end is formed in a predetermined range at both ends. This space is a space for receiving the angle fittings 3a, 4a formed in the core metal holding members 3, 4. The cylindrical mold 1 is preferably a seamless pipe, and the inner surface is preferably subjected to a fluororesin coating or an electroless plating treatment from the viewpoint of mold release.
On the other hand, the upper and core metal holding members 3 and 4 are formed with truncated cone-shaped fittings 3a and 4a that are closely fitted into the enlarged space. The chevron fittings 3a and 4a have inclined outer peripheral surfaces 3b and 4b, and the outer shape thereof is a shape that fits complementarily in the enlarged space of the cylindrical mold 1. Here, the complementary fitting means that both members are fitted so as to fill the gap on the other side.
Therefore, the taper angles of the inclined outer peripheral surfaces 3b and 4b of the angle fittings 3a and 4a and the taper angles of the inclined inner peripheral surfaces 1a and 1b of the cylindrical mold 1 are matched, and the core metal holding members 3 and 4 are the cylindrical molds. In the state of being fastened to 1, the taper surfaces are configured to be joined closely together with almost no gap. The taper angle and the height of the peaks of the angle fittings 3a and 4a are determined in consideration of both the fitting strength and workability. As the taper angle is smaller and the penetration depth of the angle fittings 3a, 4a into the cylindrical mold 1 is deeper, the positioning accuracy is improved. However, if the depth is too deep, the upper and lower cored bar holding members 3, 4 are cylindrical after molding. It becomes difficult to separate from the mold 1. The taper angle θ is preferably in the range of 5 to 20 °.
[0014]
Further, shaft end holding holes 3c and 4c for receiving the shaft end portions 2a and 2b of the cored bar 2 are formed at the centers of the top surfaces of the angle fittings 3a and 4a, respectively. The shaft end holding holes 3 c and 4 c correspond to the shape of the shaft end of the core metal 2.
The clearance between the shaft end holding holes 3c, 4c provided in the upper and lower cored bar holding members 3, 4 and the shaft end parts 2a, 2b of the cored bar 2 is preferably set to 5 to 25 μm. Considering that the shaft diameter variation of the cored bar 2 is usually about 5 μm, if the gap is smaller than this, the cored bar 2 may not be inserted. Moreover, if it inserts forcibly, bending and buckling stress will generate | occur | produce in a metal core and runout will increase. On the other hand, if the gap is larger than 25 μm, the degree of eccentricity increases and the deflection increases.
The depth of the shaft end holding holes 3c, 4c should be determined so that the core metal 2 does not buckle when the core metal holding members 3, 4 are fastened to both ends of the cylindrical mold 1. It is set to 1 mm to 20.2 mm (however, the length of the core metal at both ends where the resin of the roller molded product is not coated, that is, the shaft end length is 20.0 mm). The clearance between the total length of the cored bar 2 and the distance between the shaft end holding hole bottom surfaces 3d and 4d is preferably set in the range of 0.05 to 1 mm.
[0015]
The base mold 10 is provided with a through hole 11 into which the cylindrical mold 1 is loaded. The cylindrical mold 1 is loaded into the through hole 11, and the opening portions at both ends of the cylindrical mold 1 are further provided. It is closed by the core metal holding members 3 and 4. The purpose of the base mold 10 is to clamp the cylindrical mold 1 and the core metal holding members 3 and 4 with high accuracy. The hole diameter of the through hole 11 of the base mold 10 is preferably 0.01 to 0.5 mm larger than the outer diameter of the core metal holding members 3 and 4. If it is 0.01 mm or less, it becomes difficult to attach and detach the cylindrical mold 1 and the base mold 10, and if it exceeds 0.5 mm, this space acts as a kind of heat insulating space, so that the thermal conductivity during heat curing is high. It will worsen and the curing time will be extended.
[0016]
The upper and lower outer peripheries of the base mold 10 are formed with flanges 10a and 10b, and the outer peripheral surfaces of the core metal holding members 3 and 4 are formed with corresponding flanges 3e and 4e. The flange portions 10a and 10b and the flange portions 3e and 4e of the cored bar holding members 3 and 4 face each other and are paired. These collars have a flat surface facing each other and an inclined surface on the back side. The formation positions of the flange portions are the inclined outer peripheral surfaces 3b of the angle fittings 3a, 4a when the flange portions 10a, 10b of the base mold 10 and the flange portions 3e, 4e of the core metal holding members 3, 4 are opposed to each other. 4b and the inclined inner peripheral surfaces 1a, 1b of the cylindrical mold 1 are set so as to contact each other over the entire surface, and the upper and lower chevron fitting bodies 3a, 4a are complementarily densely packed in the diameter expansion space of the cylindrical mold 1. It is set so that it fits. At this time, the shaft end portions 2a and 2b of the cored bar 2 are designed to be accommodated in the shaft end holding holes 3c and 4c.
In order to realize such a design, the axial length of the cylindrical mold 1 and the axial length of the base mold 10 need to be equal. When the axial length of the cylindrical mold 1 is shorter than the axial length of the base mold 10, the flange portions 10 a and 10 b of the base mold 10 and the flange portions 3 e and 4 e of the core metal holding members 3 and 4 are connected. When facing each other, the inclined outer peripheral surfaces 3b, 4b of the angle fittings 3a, 4a and the inclined inner peripheral surfaces 1a, 1b of the cylindrical mold 1 are not brought into contact with each other, and the cylindrical mold 1 is not fixed. .
[0017]
Various methods for fastening the core metal holding members 3 and 4 to the base mold 10 are conceivable. In this embodiment, a ferrule clamp is used, and the collar portion is fastened by fastening the collar portion with the ferrule clamp. You may bolt the collar parts which contact | abutted without using a ferrule clamp. By joining the flange portions, it is possible to prevent the cored bar holding members 3 and 4 from being fastened while being tilted with respect to the cylindrical mold 1.
[0018]
The setting of the cored bar 2 in the apparatus of the present embodiment having such a configuration is performed as follows. First, one end of the cored bar 2 is held by the lower cored bar holding member 4, and the cylindrical mold 1 is lowered with respect to the lower cored bar holding member 4 in this state so that the angle fitting 4 a of the lower cored bar holding member 4 is moved. The cylindrical mold 1 is inserted into the diameter-enlarged space and is pushed in until it hits the inclined inner peripheral surface 1b of the cylindrical mold 1. The abutment is performed by the surface contact of the inclined inner peripheral surface 1b of the cylindrical mold 1 and the tapered surface of the chevron fitting body 4a over the entire surface.
Next, the base mold 10 is lowered from above the cylindrical mold 1 and loaded into the cylindrical mold 1. The abutment is performed when the flange portions 10a and 10b of the base mold 10 and the flange portion 4e of the lower core metal holding member 4 come into contact with each other. Next, the collar portion that has come into contact is tightened by the ferrule clamp 22. When the ferrule clamp 22 is tightened, the inner peripheral edge 22a of the ferrule clamp 22 moves inward along the flange inclined surfaces 4f and 10c, and a component force in the fastening direction acts on the facing flange. Further, the fitting position of the lower core metal holding member 4 with respect to the cylindrical mold 1 is corrected by tightening until the flanges come into contact with each other, so that the core metal holding members 3 and 4 are prevented from being tilted and fastened. . The fastening strength is adjusted by the amount of biting into the collar portion of the ferrule clamp 22.
Next, the upper core metal holding member 3 is lowered from above the cylindrical mold 1, the chevron fitting body 3 a is inserted into the cylindrical mold 1, and the upper core metal holding member 3 is brought into contact with the cylindrical mold 1. After the positioning, the flanges 3e and 10a brought into contact with each other are fastened by the ferrule clamp 21, and then the curable liquid resin is filled into the molding space.
In this device, the holding position of the core metal is simply pushed to the position where the inclined outer peripheral surface of the angle fitting formed on the core metal holding member contacts the inclined inner peripheral surface of the cylindrical mold. A roller that is accurately positioned at the design position in the radial direction of the mold and has no runout can be obtained. In addition, these operations do not require delicate adjustments that must be relied on manually as in the case of tightening along conventional screw grooves, so that they are suitable for automation and can produce rollers at low cost.
[0019]
When the curable liquid resin is filled in the molding space, the mold is then heated, whereby the curable liquid resin is subjected to an addition reaction and cured. The heating means is not particularly limited, such as hot air, infrared rays, and high frequency induction heating. After completion of the curing reaction, the mold is cooled and decomposed. When the cooling is sufficiently performed, the molded product contracts more easily, so that the mold release is easily performed.
[0020]
To remove the molded product, first, the ferrule clamps 21 and 22 are loosened, the upper and lower core metal holding members 3 and 4 are removed, and then the cylindrical mold 1 is removed from the base mold 10. Then, the molded product in the cylindrical mold 1 is released by pressing the core metal 2 or the like. After mold release, clean and inspect the mold, and then reassemble and repeat the molding. By repeating this molding, the inner surface of the cylindrical mold 1 deteriorates, so that only the cylindrical mold is replaced at an appropriate time. The replacement may be a replacement with a completely new cylindrical mold, or a replacement with a deteriorated cylindrical mold that has been subjected to maintenance such as re-plating treatment and regenerated. Since the cylindrical mold is simply built in the base mold, the replacement of the cylindrical mold is extremely easy.
[0021]
【The invention's effect】
As described above, the roller manufacturing apparatus according to the present invention has a cartridge type that can replace a cylindrical mold that has a large degree of deterioration such as wear by repeated molding, and has a simple shape without adding an extra function. A mechanism that enables easy and accurate positioning of the cored bar in the cylindrical mold is used, and a mechanism that can be automated without the need for delicate adjustments that require manual labor when clamping the mold is adopted. The roller manufacturing cost can be greatly reduced.
[0022]
If the clearance between the outer diameter of the cylindrical mold and the inner diameter of the base mold is 0.01 to 0.5 mm as in claim 2, good heat conduction from the base mold to the cylindrical mold is maintained. However, the cylindrical mold can be easily attached and detached.
[0023]
According to the fourth aspect of the present invention, the ferrule clamp is formed by forming the back surface side of the joining planned surface of the flange portion facing each other as an inclined surface and fastening the outer surface of the flange portion in contact with the ferrule clamp. The mold is clamped and the core metal is corrected to a predetermined posture simply by tightening.
[0024]
When the synthetic resin layer covering the outer periphery of the metal core is made of a curable liquid resin as described in claim 5, it can be injected at a low injection pressure because of its low viscosity.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an embodiment of a roller manufacturing apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view of a conventional roller manufacturing apparatus.
DESCRIPTION OF SYMBOLS 1 Cylindrical metal mold | die 1a, 1b Inclined inner peripheral surface 2 Core metal 2a, 2b Shaft end part 3 Upper core metal holding member 4 Lower core metal holding member 3a, 4a Angle-shaped fitting body 3e, 4e Gutter part 3b, 4b Inclined outer peripheral surface 3c, 4c Shaft end holding holes 3d, 4d Shaft end holding hole bottom surface 10 Base mold 10a, 10b Hook 10c Hook inclined surface 11 Through holes 21, 22 Ferrule clamp 22a Inner peripheral edge 30 Roller forming space 41 Cylindrical mold 42 Core metal 42a, 42b Core metal end 43, 44 Core metal holding member 44b Resin injection hole 43a, 44a Metal core holding hole 45, 46 Cover member 45, 46 Cover member 47 Pin 49 Nozzle mounting hole 50 Gas vent hole 60 Roller Molding space

Claims (5)

  An apparatus for manufacturing a roller in which a synthetic resin layer is coated on the outer periphery of a metal core in the longitudinal direction, and has a cylindrical shape in which a metal core is provided with a synthetic resin filling space around the metal core, and has a predetermined range from the opening end. A cylindrical mold that forms an inclined inner peripheral surface and has a space in which the inner diameter expands toward the opening end in a predetermined range at both ends, and an end portion of the core metal that is disposed at both ends of the cylindrical mold. The diameter of the cylindrical mold, which is a member that closes the opening end of the cylindrical mold while holding, has an inclined outer peripheral surface, and has a shaft end holding hole that receives and holds the shaft end of the core metal in the radial center. A cored bar holding member provided with a chevron fitting that complementarily fits in the space, and a member that covers the outer peripheral surface of the cylindrical mold, and for mounting the cylindrical mold, the cylindrical mold A base mold having a through hole with an inner diameter slightly larger than an outer diameter, and the core metal holding member are connected to the base Roller manufacturing and means for fastening the ends of the metal molds.   The roller manufacturing apparatus according to claim 1, wherein a clearance between the outer diameter of the cylindrical mold and the inner diameter of the base mold is 0.01 to 0.5 mm. When the flanges of the base mold and the core metal holding member are provided to face each other, and when the collar part of the base mold and the collar part of the core metal holding member face each other, inclined outer peripheral surface and the inclined inner peripheral surface of the cylindrical mold is set at a position abutting relationship over the entire surface, such that the chevron fitting member is complementarily tightly fitted in enlarged space of the tubular mold The roller manufacturing apparatus according to claim 1, wherein a forming position of the collar portion is set.   The roller manufacturing apparatus according to claim 3, wherein a back side of the face to be joined of the flanges facing each other is an inclined surface, and an outer surface of the flange in contact is fastened with a ferrule clamp.   The roller manufacturing apparatus according to any one of claims 1 to 4, wherein the synthetic resin layer covering the outer periphery of the metal core is made of a curable liquid resin.

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